1 Yahweh is my shepherd:

A shepherd’s job and life are spent in a selfless manner.  The sheep dominate the shepherd's life day in and day out.  How to provide for them?  Where to lead them?  Are there any dangers ahead or behind them? Here David is showing the relationship God's people should accept. God the good shepherd, his people the sheep.

I shall lack nothing.

 It is by His loving care we are thoroughly and completely cared and provided for. 
2 He makes me lie down in green pastures.
    He leads me beside still waters.

In our relationship with God, we find a peace that can’t be found anywhere else.
3 He restores my soul.

This life can wear people down. Especially when they insist on going their own way.  As the shepherd leads his sheep to places of refreshing, God stands ready to restore the weary and broken soul.
    He guides me in the paths of righteousness for his name’s sake.

God gives direction for the purpose of leading His people who will choose to follow Him on the right path.Finding rest for your soul doesn’t just happen by being in green meadows, but it happens by staying on the true course already laid out for us through God’s Word. 
4 Even though I walk through the valley of the shadow of death,
    I will fear no evil, for you are with me.

The presence of the Shepherd should make us feel safe.
Your rod and your staff,
    they comfort me.

The shepherd’s rod and staff were used as tools of protection from enemies and from self. Not only will they defend us from danger, they are used to guide us in the path our Lord has set out for us.
5 You prepare a table before me

The Shepherd not only is the comfort of His people, but He goes “before” them to protect them and to provide for them.
    in the presence of my enemies.
You anoint my head with oil.

 “Oil” represents care and devotion to the one it is applied to, which is what God does for His people.
    My cup runs over.

Abundant provision.  God loves His people and has no problem supplying what they need. 
6 Surely goodnessandloving kindness shall follow me all the days of my life,

God’s faithful care in this life.
    and I will dwell in Yahweh’s house forever.

This is the assurance we find in God. We, knowing that as His child; as His people, we can look forward to spending eternity in the presence of God.  There is a blessed future for the people of God.